This invention relates to a tape cassette and, more particularly, to a thumb-sized tape cassette of extremely small dimensions which, nevertheless, provides an adequate recording capacity on a magnetic tape housed therewithin.
The use of magnetic tape cartridges to house magnetic tape upon which signals are recorded and reproduced is well known and advantageous. The cartridge provides a secure and protected environment for the magnetic tape housed therein. When housed in a cartridge, the magnetic tape may be easily loaded and removed from a record/reproducing device, may be easily transported and may be readily stored.
Various types and configurations of magnetic tape cartridges have been proposed and utilized. For example, so-called 8-track cartridges are provided with an endless reel of tape that is guided in a run across access ports, or openings, in a peripheral wall of the cartridge to enable suitable processing elements, such as transducers, capstans and the like to engage the tape. Another conventional tape cartridge is the so-called "standard" cassette. Typically, a standard cassette is a housed reel-to-reel device wherein magnetic tape is guided in a run between supply and take-up reels. A central opening in the front peripheral wall of the cassette is provided to receive the transducer, and opposite side openings in the front wall are provided to receive a pinch roller. Axially-aligned holes are provided in the top and bottom walls of the cassette to receive a capstan which is positioned behind the tape run and cooperates with the pinch roller inserted into a side opening so as to "pinch" the tape therebetween and drive the tape between the supply and take-up reels. To provide proper contact between the transducer and the magnetic tape, a pressure pad normally is spring-mounted behind the tape run in the vicinity of the central opening of the front peripheral wall. The tape is driven at a relatively low speed, such as on the order of about 17/8 inches per second.
In an effort to reduce the size of the "standard" cassette, the so-called "minicassette" has been developed. The minicassette also is a rectangular housed reel-to-reel tape device. However, in the minicassette, the supply and take-up reels are driven directly to transport the tape therebetween. The minicassette thus avoids the capstan-pinch roller arrangement. Unfortunately, in reducing the size of the cassette housing, the quantity of tape that may be stored therein also has been reduced. Whereas a typical "standard" cassette stores a sufficient quantity of tape so as to permit continuous recording of up to, for example, 90 minutes, the amount of tape housed within a typical "minicassette" is sufficient to permit continuous recording on the order of about twenty minutes.
In a still further attempt to reduce the size of the tape cartridge, the "microcassette" has been developed. Although substantially reduced in size relative to the "standard" cassette, the microcassette nevertheless is a capstan-driven, reel-to-reel tape device. The capstan is inserted immediately behind the central portion of the run of tape past the front peripheral wall, and this front wall is provided with numerous openings to receive a pinch roller and, on opposite sides of the pinch roller, one or more transducers. The speed at which the tape is transported has been reduced to 15/16 inches per second so as to obtain a continuous recording capacity on the order of about thirty minutes. A further speed reduction so as to effect a transport speed on the order of 15/32 inches per second has been achieved so as to double the recording capacity. However, at this very slow tape speed, the quality of the recorded signals, such as audio signals, is noticeably degraded.
It is desirable to provide a still further reduction in the size of a tape cassette yet not sacrifice the amount of continuous recording time that is available on that cassette and, moreover, to minimize degradation in the quality of the recorded signals that inherently occurs when the transport speed of the cassette tape is reduced. However, as the size of the tape housing is reduced, there is little, if any, room therein in which the usual tape guides, support ribs or pressure pad assembly may be provided. Furthermore, if substantially all of the housing is provided with tape, there is little, if any, room in which openings may be used for positioning the tape cassette when loaded into a tape record/reproducing device. Moreover, in view of the limited space within the housing, a symmetrical arrangement is desirable so that the cassette may be utilized, on either "side" by the same record/reproducing device, that is, signals may be recorded on both longitudinal halves of the tape, and still provide good contact between the tape and the transducer and also between the tape and the capstan-pinch roller combination.